Deposition radial and edge profile tunability through independent control of TEOS flow

ABSTRACT

Disclosed embodiments generally relate to a processing chamber that includes a perforated lid, a gas blocker disposed on the perforated lid, and a substrate support disposed below the perforated lid. The gas blocker includes a gas manifold, a central gas channel formed in the gas manifold, a first gas distribution plate that includes inner and outer trenches surrounding the central gas channel, and a first and second gas channels formed in the gas manifold. The first gas channel is in fluid communication with a first gas source and the inner trench, and the second gas channel is in fluid communication with the first gas source and the outer trench and a second gas distribution plate The first gas channel is in further fluid communication with a third gas distribution plate that is disposed below the second gas distribution plate, and a plurality of pass-through channels that are disposed between the second gas distribution plate and the third gas distribution plate. The second gas distribution plate includes a plurality of through holes formed through a bottom of the second gas distribution plate as well as a central opening in fluid communication with the central gas channel The second gas distribution plate further includes a recess region formed in a top surface of the second gas distribution plate, and the recess region surrounds the central opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationSer. No. 62/516,050, filed Jun. 6, 2017, which is herein incorporated byreference.

BACKGROUND Field

Embodiments of the disclosure generally relate to an improved method andapparatus for controlling deposition near an edge of the substrate.

Description of the Related Art

Plasma enhanced chemical vapor deposition (PECVD) is generally employedto deposit thin films on a substrate such as a flat panel orsemiconductor wafer. Plasma enhanced chemical vapor deposition isgenerally accomplished by introducing a precursor gas into a vacuumchamber that contains a substrate. The precursor gas is typicallydirected through a distribution plate disposed near the top of thechamber. The precursor gas in the chamber is energized (e.g., excited)to form a plasma by applying RF power to the chamber from one or more RFsources coupled to the chamber. The excited gas reacts to form a layerof material on a surface of the substrate that is positioned on atemperature controlled substrate support.

It has been observed that the distribution of precursor gases in thechamber may result in varying plasma densities across the surface of thesubstrate, causing different deposition rates between the center and theedge of the substrate. Therefore, there is a need in the art for animproved method and apparatus with better control of gas distribution.

SUMMARY OF THE DISCLOSURE

In one embodiment, a processing chamber for processing a substrate isprovided. The processing chamber includes a perforated lid, a gasblocker disposed on the perforated lid, and a substrate support disposedbelow the perforated lid. The gas blocker includes a gas manifold, acentral gas channel formed in the gas manifold, a first gas distributionplate disposed below the gas manifold, the first gas distribution platecomprising an inner trench surrounding the central gas channel and anouter trench surrounding the inner trench, a first gas channel formed inthe gas manifold, the first gas channel having a first end in fluidcommunication with a first gas source and a second end in fluidcommunication with the inner trench, a second gas channel formed in thegas manifold, the second gas channel having a first end in fluidcommunication with the first gas source and a second end in fluidcommunication with the outer trench, a second gas distribution platedisposed below the first gas distribution plate, a third gasdistribution plate disposed below the second gas distribution plate, thethird gas distribution plate comprising a plurality of through holesformed through a bottom of the third gas distribution plate, and thethird gas distribution plate contacting a top surface of the perforatedlid, and a plurality of pass-through channels disposed between thesecond gas distribution plate and the third gas distribution plate, andeach pass-through channel being extended through the perforated lid. Thesecond gas distribution plate includes a plurality of through holesformed through a bottom of the second gas distribution plate, a centralopening in fluid communication with the central gas channel, and arecess region formed in a top surface of the second gas distributionplate, the recess region surrounds the central opening.

In another embodiment, the processing chamber includes a first gassource comprising a first gas line and a second gas line, a perforatedlid, a gas blocker disposed on the perforated lid, and a substratesupport disposed below the perforated lid, the substrate support havinga substrate supporting surface. The gas blocker includes a gas manifold,a central gas channel formed in the gas manifold, a first gasdistribution plate disposed below the gas manifold, the first gasdistribution plate comprising an inner trench surrounding the centralgas channel and an outer trench surrounding the inner trench, a firstgas channel formed in the gas manifold, the first gas channel having afirst end in fluid communication with the first gas line and a secondend in fluid communication with the inner trench, a second gas channelformed in the gas manifold, the second gas channel having a first end influid communication with the second gas line and a second end in fluidcommunication with the outer trench, a second gas distribution platedisposed below the first gas distribution plate, the second gasdistribution plate comprising a plurality of through holes formedthrough a bottom of the second gas distribution plate, a third gasdistribution plate disposed below the second gas distribution plate, andthe third gas distribution plate comprising a plurality of through holesformed through a bottom of the third gas distribution plate, and thethird gas distribution plate contacts a top surface of the perforatedlid.

In yet another embodiment, a process system for processing a substrateis provided. The process system includes a first gas source comprising afirst gas line, a second gas line, a third gas line, and a fourth gasline, a second gas source comprising a fifth gas line and a sixth gasline, a first processing chamber, and a second processing chamberseparated from the first processing chamber. The first processingchamber includes a perforated lid, a gas blocker disposed on theperforated lid, and a substrate support having a substrate supportingsurface, the substrate supporting surface and the perforated lid definea substrate processing region therebetween. The gas blocker of the firstprocessing chamber includes a gas manifold, a first gas distributionplate disposed below the gas manifold, the first gas distribution platecomprising an inner trench and an outer trench formed in a top surfaceof the first gas distribution plate, the inner trench and the outertrench are arranged in two concentric circles, a central gas channelformed through at least the gas manifold and the first gas distributionplate, the central gas channel in fluid communication with the secondgas source through the fifth gas line, and the central gas channel issurrounded by the inner trench and the outer trench, a first gas channelformed through at least a portion of the gas manifold and disposedradially outward of the central gas channel, the first gas channelhaving a first end in fluid communication with the first gas line and asecond end in fluid communication with the inner trench, and a secondgas channel formed through at least a portion of the gas manifold anddisposed radially outward of the first gas channel, the second gaschannel having a first end in fluid communication with the second gasline and a second end in fluid communication with the outer trench. Thesecond processing chamber includes a perforated lid, a gas blockerdisposed on the perforated lid of the second processing chamber, and asubstrate support having a substrate supporting surface, the substratesupporting surface and the perforated lid defining a substrateprocessing region therebetween. The gas blocker of the second processingchamber includes a gas manifold, a first gas distribution plate disposedbelow the gas manifold, the first gas distribution plate comprising aninner trench and an outer trench formed in a top surface of the firstgas distribution plate, the inner trench and the outer trench arearranged in two concentric circles, a central gas channel formed throughat least the gas manifold and the first gas distribution plate, thecentral gas channel in fluid communication with the second gas sourcethrough the sixth gas line, and the central gas channel is surrounded bythe inner trench and the outer trench, a first gas channel formedthrough at least a portion of the gas manifold and disposed radiallyoutward of the central gas channel, the first gas channel having a firstend in fluid communication with the third gas line and a second end influid communication with the inner trench, and a second gas channelformed through at least a portion of the gas manifold and disposedradially outward of the first gas channel, the second gas channel havinga first end in fluid communication with the fourth gas line and a secondend in fluid communication with the outer trench.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 depicts a top view of an exemplary tandem processing systemaccording to embodiments of the present disclosure.

FIG. 2 depicts a cross-sectional view of a processing chamber of thetandem processing system according to embodiments of the presentdisclosure.

FIG. 3 illustrates exemplary flow path of the gas flow of gas mixturesaccording to embodiments of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, wherever possible, to designate identical elements that are commonto the figures.

DETAILED DESCRIPTION

FIG. 1 depicts a top view of an exemplary tandem processing system 100according to embodiments of the present disclosure. The processingsystem 100 includes two separate and adjacent processing chambers 101,103 for processing the substrates. The processing chambers 101, 103 canshare a first gas source 112 disposed adjacent to the processingchambers 101, 103. The first gas source 112 is coupled to the processingchambers 101, 103 through a first gas line 118 and a second gas line119, respectively. The exemplary tandem processing system 100 may beincorporated into a processing system, such as a Producer™ processingsystem, commercially available from Applied Materials, Inc., of SantaClara, Calif. It is to be understood that the disclosure also hasutility in processing systems manufactured by other manufacturers.

The first gas source 112 may include a vaporizer 145 for vaporizingliquid precursor, such as tetraethoxysilane (TEOS). At least one heater147 is coupled to the vaporizer 145 and heats the liquid precursor intoa gas phase. The precursor gas is delivered to the first gas line 118and/or the second gas line 119 and then to the processing chambers 101,103. The first gas source 112 may contain one or more precursor sources,depending on the application. In some embodiments, the first gas source112 may contain a source for a first gas mixture and a source for asecond gas mixture. The first gas mixture may flow through the first gasline 118 and the second gas mixture may flow through the second gas line119.

The first gas mixture and the second gas mixture may be suitable fordepositing a dielectric material, such as silicon oxides. In oneembodiment, the first gas mixture includes an oxygen-containing gas, asilicon-containing gas, and a carrier gas, while the second gas mixtureincludes the oxygen-containing gas and the carrier gas, or vice versa.Suitable oxygen-containing gas may include oxygen (O₂), ozone (O₃),carbon dioxide (CO₂), carbon monoxide (CO), nitrous oxide (N₂O), nitrousoxide (N₂O), nitric oxide (NO), or any combination thereof. Suitablesilicon-containing gas may include silanes, halogenated silanes,organosilanes, and any combinations thereof. Silanes may include silane(SiH₄), tetraethoxysilane (TEOS), and higher silanes with the empiricalformula Si_(x)H_((2x+2)), such as disilane (Si₂H₆), trisilane (Si₃H₈),and tetrasilane (Si₄H₁₀), or other higher order silanes such aspolychlorosilane. Suitable carrier gases include argon, nitrogen,hydrogen, helium, or other suitable inert gases. Carrier gas may be usedfor carrying vaporized silicon-containing gas, such as TEOS.

In some embodiments, a second gas source 123 may be coupled to, througha third gas line 125, a central gas channel 129 of the processingchambers 101, 103. The central gas channel 129 is in fluid communicationwith the substrate processing region 108 (FIG. 2) of the processingchambers 101, 103. The second gas source 123 may include any suitableprocess precursor, such as the silicon-containing gas discussed above.Likewise, the second gas source 123 may include a vaporizer (not shown)and a heater (not shown) for vaporizing liquid precursor, such as TEOS.In an embodiment, the second gas source 123 includes a source of a thirdgas mixture containing silanes, such as TEOS.

In various embodiments to be discussed below, the first gas mixture andthe second gas mixture may be routed to the inner gas zone 120 and outergas zone 142 of the substrate processing region 108, respectively. Thethird gas mixture may be provided to the central gas channel 129. Thethird gas mixture, the first gas mixture and the second gas mixture areexcited to form a plasma using capacitive or inductive means. These gasmixtures are decomposed in the plasma to deposit a layer of oxide, e.g.,silicon oxide, on the surface of a substrate located in the processingchambers 101, 103.

FIG. 2 depicts a cross-sectional view of the processing chamber 101according to embodiments of the present disclosure. It should beunderstood that while only a portion of the processing system 100, e.g.,the processing chamber 101, is shown, the description for the processingchamber 101 is equally applicable to the processing chamber 103 sincethe configuration of the processing chambers 101, 103 are substantiallyidentical. Therefore, the operation and processing occurred in theprocessing chamber 101 can similarly and concurrently be performed inthe processing chamber 103. The processing chamber 101 has a perforatedlid 102, a gas blocker 105 disposed on the perforated lid 102, a chamberwall 104, and a bottom 106. The perforated lid 102, the chamber wall 104and the bottom define the substrate processing region 108 where asubstrate (not shown) is to be disposed. The substrate processing region108 can be accessed through a port (not shown) in the chamber wall 104that facilitates movement of the substrate into and out of theprocessing chamber 101.

A substrate support 109 is disposed within the processing chamber 101and surrounded by the chamber wall 104. The substrate supporting surfaceof the substrate support 109 may have a plurality of holes 242distributed evenly across the substrate supporting surface. The holes242 are adapted to permit the flow of gases through the substratesupporting surface for cooling or heating of the substrate disposedthereon. The substrate support 109 may couple to a stem 131 that extendsthrough the bottom 106 of the processing chamber 101. The stem 131 canbe operated by a drive system (not shown) to move the substrate support109 up and down, thereby changing the position of the substrate in thesubstrate processing region 108. The drive system can also rotate and/ortranslate the substrate support 109 during processing. The substratesupport 109 and the substrate processing region 108 are configured toaccommodate substrate having a nominal diameter size up to 12 inch (300mm), 18 inch (450 mm), or other diameter.

The perforated lid 102 is supported by the chamber walls 104 and can beremoved to service the interior of the processing chamber 101. Theperforated lid 102 is generally comprised of aluminum, aluminum oxide,aluminum nitride, stainless steel, or any other suitable material. Thegas blocker 105 disposed on the perforated lid 102 is a dual zone gasblocker configured to independently control the flow of two or more gasmixtures into the substrate processing region 108. The gas blocker 105is in fluid communication with the first gas source 112 and the secondgas source 123. In an example as shown, the first gas source 112 isconnected to the gas blocker 105 through the first gas line 118 and thesecond gas line 119, respectively. The first gas line 118 may beconnected to the first gas source 112 to provide the first gas mixture,e.g., the silicon-containing gas, the oxygen-containing gas, and thecarrier gas, into the processing chamber 101. The second gas line 119may be connected to the first gas source 112 to provide the second gasmixture, e.g., oxygen-containing gas and the carrier gas, into theprocessing chamber 101. The first gas line 118 may be heated andactively controlled to ensure that gas (e.g., TEOS) remains in the gasphase while traveling with the carrier gas to the processing chamber101.

The gas blocker 105 generally includes a gas manifold 212, a first gasdistribution plate 214 disposed below the gas manifold 212, a second gasdistribution plate 216 disposed below the first gas distribution plate214, and a third gas distribution plate 218 disposed below the secondgas distribution plate 216. The central gas channel 129 is formedthrough at least the gas manifold 212 and the first gas distributionplate 214. The gas manifold 212, the first gas distribution plate 214,the second gas distribution plate 216, and the third gas distributionplate 218 are concentrically disposed about a central axis passingthrough the longitudinal axis of the central gas channel 129. The firstgas distribution plate 214 may include one or more heat transfer fluidchannels 121. The heat transfer fluid channels 121 can be used forregulating the temperature of the gas blocker 105 and/or the perforatedlid 102 by flowing heat transfer fluid therethrough. Suitable heattransfer fluid may include, but is not limited to, water, air, helium,etc. The first gas distribution plate 214 may also include a pumpingplenum 114 that fluidly connects the substrate processing region 108 toan exhaust port (that includes various pumping components, not shown).

The second gas distribution plate 216 has a central opening 124, and arecess region 128 formed in the top surface of the second gasdistribution plate 216. The recess region 128 surrounds the centralopening 124 and extends radially between the central opening 124 and theedge of the second gas distribution plate 216. The bottom of the firstgas distribution plate 214 and the bottom of the second gas distributionplate 216 define a plenum for the recess region 128. The central opening124 is in fluid communication with the central gas channel 129. In anembodiment, the central opening 124 has a diameter greater than thediameter of the central gas channel 129. The second gas distributionplate 216 has a plurality of through holes 126 formed through the bottomof the second gas distribution plate 216. The through holes 126 may bearranged in any suitable pattern. In one embodiment, the through holes126 are arranged in multiple concentric rings of increasing diameter.

The third gas distribution plate 218 has a recess region 220 formed inthe top surface of the third gas distribution plate 218. The bottom ofthe third gas distribution plate 218 contacts a top surface of theperforated lid 102. The bottom of the second gas distribution plate 216and the bottom of the third gas distribution plate 218 define a plenumfor the recess region 220. An inner ring 138 and an outer ring 140 areconcentrically disposed on the bottom of the third gas distributionplate 216 between the second gas distribution plate 216 and the thirdgas distribution plate 218. The outer ring 140 surrounds the inner ring138. The inner ring 138 and the outer ring 140 may be fabricated fromaluminum, aluminum oxide, aluminum nitride, stainless steel, or othersuitable material such as dielectric material. The inner ring 138 andthe outer ring 140 can separate the recess region 220 into an inner gaszone 120 and an outer gas zone 142. For example, the region radiallyinward of the inner ring 138 can be defined as the inner gas zone 120.The region between the inner ring 138 and the outer ring 140 and theregion radially outward of the outer ring 140 can be collectivelydefined as the outer gas zone 142. In cases where the third gasdistribution plate has a diameter of about 360 mm, the inner gas zone120 may start at a radial distance of about 20 mm or greater, forexample about 30 mm to about 60 mm. The outer gas zone 142 may start ata radial distance of about 60 mm or greater, for example about 75 mm to110 mm, measuring from the center of the third gas distribution plate218.

The third gas distribution plate 218 has a plurality of through holes132 formed through the bottom of the third gas distribution plate 218.The through holes 132 of the third gas distribution plate 218 may have adensity greater than the density of the through holes 126 of the secondgas distribution plate 216. In an example, the ratio of the density ofthe through holes 132 to the density of the through holes 126 can be ina range of about 1.5:1 to about 5:1, for example about 2:1 to about 3:1.The through holes 132 may be arranged in a radial pattern across thediameter of the third gas distribution plate 218 to allow uniformdelivery of the gas into the substrate processing region 108.

The gas blocker 105 also includes a first gas channel 116 and a secondgas channel 117. The first gas channel 116 and the second gas channel117 are disposed to extend through at least a portion of the gasmanifold 212. The first gas channel 116 is disposed radially outward ofthe central gas channel 129, and the second gas channel 117 is disposedradially outward of the first gas channel 116. The first gas channel 116has a first end connected to, or in fluid communication with, the firstgas line 118, and a second end connected to, or in fluid communicationwith, an inner trench 222 formed in the top surface of the first gasdistribution plate 214. Similarly, the second gas channel 117 has afirst end connected to, or in fluid communication with, the second gasline 119, and a second end connected to, or in fluid communication with,an outer trench 224 formed in the top surface of the first gasdistribution plate 214. The inner trench 222 and the outer trench 224are arranged in two concentric circles surrounding the central gaschannel 129. The first gas channel 116 may be disposed at any locationalong the inner trench 222, and the second gas channel 117 may bedisposed at any location along the outer trench 224. The inner trench222 has a first depth D1 measuring from the top surface of the first gasdistribution plate 214. The outer trench 224 has a second depth D2measuring from the top surface of the first gas distribution plate 214.The first depth D1 may be shorter or greater than the second depth D2.In an example as shown, the first depth D1 is greater than the seconddepth D2. In an example, the ratio of the first depth D1 to the seconddepth D2 is about 1.1:1 to about 1.5:1, for example about 1.3:1.

In some embodiments, the gas blocker 105 may include a third gas channel240 disposed through at least a portion of the gas manifold 212. Thethird gas channel 240 may be in fluid communication with the first andsecond gas sources 112, 123, or any other gas source containing anysuitable gas source (e.g., nitrogen-containing gas source, or adopant-containing gas source etc.) needed for the application. Likewise,the third gas channel 240 may be disposed radially outward of thecentral gas channel 129, and the third gas channel 240 may be disposedat any location along the inner trench 222 so that the third gas channel240 and the inner trench 222 are in fluid communication with each other.

The inner trench 222 is in fluid communication with the inner gas zone120 through one or more inner gas channels 226 also formed in the firstgas distribution plate 214. The placement of the inner ring 138 confinesthe gas mixture (e.g., first gas mixture) flowing from the first gaschannel 116 to the inner gas zone 120. The first gas mixture is thenflowed through the perforated lid 102 and to the inner region of thesubstrate processing region 108. The inner region of the substrateprocessing region 108 (and thus the substrate disposed on the substratesupport 109) substantially corresponds to the inner gas zone 120. Thearrow 230 illustrates a possible flow path of the gas mixture from thefirst gas line 118 to the substrate processing region 108. Likewise, theouter trench 224 is in fluid communication with the recess region 128 ofthe second gas distribution plate 216 through one or more outer gaschannels 228 also formed in the first gas distribution plate 214. Theplacement of the outer ring 140 confines the gas mixture (e.g., secondgas mixture) flowing from the second gas channel 117 to the recessregion 128 and into the outer gas zone 142. The second gas mixture isthen flowed through perforated lid 102 and to the outer region of thesubstrate processing region 108. The outer region of the substrateprocessing region 108 (and thus the substrate disposed on the substratesupport 109) substantially corresponds to the outer gas zone 142. Whilenot shown, it should be understood that the perforated lid 102 hasthrough holes corresponding to the through holes 132 of the third gasdistribution plate 218. The arrow 236 illustrates a possible flow pathof the gas mixture from the second gas line 119 to the substrateprocessing region 108. The arrow 238 illustrates a possible flow path ofthe gas mixture from the third gas line 125 to the substrate processingregion 108.

In some embodiments, the gas blocker 105 may include a plurality ofpass-through channels (e.g., pass-through channels 232, 234) disposedbetween the second gas distribution plate 216 and the third gasdistribution plate 218. Each pass-through channel is configured todirectly route the gas mixture (e.g., second gas mixture) from therecess region 128 of the second gas distribution plate 216 into thesubstrate processing region 108. The pass-through channels may bedisposed radially inward of the inner ring 138. The pass-throughchannels may be provided in any number. For example, four pass-throughchannels (only two pass-through channels 232, 234 are shown for clarity)may be provided and angularly separated from each other by 90 degrees.The pass-through channels 232, 234 may form through the bottom of thesecond gas distribution plate 216 and extend into the bottom of thethird gas distribution plate 218 and into the perforated lid 102. Insome embodiments, the pass-through channels may extend through theentire thickness of the perforated lid 102. The pass-through channels232, 234 allow the gas mixture (e.g., second gas mixture) to passthrough the recess region 220 without being mixed prematurely with thegas mixture (e.g., first gas mixture) flowing from the first gas channel116 and/or the gas mixture flowing through the central gas channel 129.

The perforated lid 102 and the substrate support 109 may serve as upperand bottom electrodes, respectively, for exciting and ionizing the gasmixtures in the substrate processing region 108. A bias power may beapplied to the substrate support 109. The substrate support 109 may begrounded such that the perforated lid 102 supplied with an RF power(provided by a power source 156) may serve as a cathode electrode, whilethe grounded substrate support 108 may serve as an anode electrode. Theperforated lid 102 and the substrate support 109 are operated to form anRF electric field in the substrate processing region 108. The RFelectric field can ionize the gas mixtures into a plasma. If desired,any one or more of the first, second and third gas distribution plates214, 216, 218 may serve as an electrode and operate to excite and ionizethe gas mixtures in the recess region 128, 220. The RF power, generallyhaving a frequency of between a few Hz to 13 MHz or higher, is providedin a wattage suitable for the substrate surface area. In one embodiment,the power source 156 includes a dual frequency source that provides alow frequency power at less than about 2 MHz (preferably about 200 to500 kHz) and a high frequency power at greater than 13 MHz (preferablyabout 13.56 MHz). The frequencies may be fixed or variable.Illustratively, for a 300 mm substrate, the low frequency power may beabout 0.3 to about 2 kW while the high frequency power may be about 1 toabout 5 kW.

FIG. 3 depicts a simplified cross-sectional view of the processingchamber 101 of FIG. 2 having a substrate 302 disposed on the substratesupport 109. FIG. 3 shows exemplary flow paths of the first, second, andthird gas mixtures (represented by arrows 230, 236, 238, respectively)from the first and second gas sources 112, 123 to the substrateprocessing region 108 according to embodiments of the presentdisclosure. As can be seen, the placement of the inner ring 138 and theouter ring 140 can restrict all or the majority of the first gas mixture230 from the first gas line 118 and the third gas mixture 238 from thethird gas line 125 to the inner gas zone 120, and restrict all or themajority of the second mixture gas 236 from the second gas line 119 tothe outer gas zone 142. Therefore, the first and third gas mixtures 230,238 from the first gas line 118 and third gas line 125, such as TEOS, O₂and argon, will pass the through holes of the third gas distributionplate 218 located within the inner ring 138, and flow downwardly throughthe perforated lid 102 toward the inner region of the substrateprocessing region 108. As the first and third gas mixtures 230, 238approach the substrate support 109, the flows curve into radial outwardflows along the top surface 304 of the substrate support 109. The radialoutward flows of the first and third gas mixtures 230, 238 continue tothe outer region of the substrate processing region 108, maintainingflows of the first and third gas mixtures 230, 238 from the inner regionof the substrate processing region 108 to its perimeter. In themeantime, the second gas mixture 236 from the second gas line 119, suchas oxygen and argon gases, will pass the through holes of the second andthird gas distribution plates 216, 218, and flow downwardly through theperforated lid 102 toward the outer region of the substrate processingregion 108. Particularly, as the second gas mixture 236 approaches theradial outward flows of the first and third gas mixtures 230, 238, theflow of the second gas mixture 236 curves into a radial outward flow andflows with the radial outward flows of the first and third gas mixtures230, 238 toward the edge of the substrate processing region 108. Thefirst, second, and third gas mixtures 230, 236, 238 are ionized and forma plasma while flowing into the substrate processing region 108 fordeposition of a layer, such as silicon oxide, on the substrate disposedon the substrate support 109 in an uniform manner.

It has been observed that inefficient TEOS concentration can occur nearthe edge of the substrate support 109 (and thus the substrate disposedthereon) due to the presence of surface boundary layer, which may resultin varying plasma densities across the surface of the substrate andcause different deposition rates between the center and the edge of thesubstrate. The configuration of the gas blocker 105 offers manyadvantages as it can restrict the flow of TEOS to the inner region ofthe substrate processing region 108 while allowing a dedicate flow ofthe oxygen and argon gases (e.g., second gas mixture 236) to the outerregion of the substrate processing region 108. The addition of oxygenand argon gas (e.g., second gas mixture 236) to the outer region of thesubstrate processing region 108 can confine the flow of TEOS, O₂ and Ar(e.g., first and third gas mixtures 230, 238) within the inner region ofthe substrate processing region 108 and maintain the residence time ofTEOS within the inner region of the substrate processing region 108. Theaddition of oxygen and argon gas to the outer region of the substrateprocessing region 108 can also promote gas reaction at or near the edgeof the substrate support 105, thereby enhancing the TEOS concentrationnear the edge of the substrate. Since the TEOS concentration at the edgeof the substrate is increased, the plasma density at the substrate edgeduring processing can be increased accordingly. As a result, a uniformdeposition rate between the center and the edge of the substrate can beobtained.

Moreover, it has been observed that the arrangement of the inner ring138 and the outer ring 140 can be used to adjust the film depositionrate (and thus the film profile across the substrate surface). Forexample, the outer peripheral surface of the inner ring 138 may bedisposed at a radial distance of about 75 mm, for example about 80 mm to90 mm, measuring from the center of the substrate 110, to provide gassplit of about 27% of the total gas flow at the inner gas zone 120 andabout 73% of the total gas flow at the outer gas zone 142. The termtotal gas flow described herein refers to total flow of the gas mixturespresent in the recess region 220. This arrangement can yield gooddeposition uniformity across the substrate surface.

Furthermore, it has been observed that varying about 2-4% of TEOS flow(negligible amount of flow in the total process flow) in the innerregion of the substrate processing region 108 can result in about 5-10%change in deposition rates and film profile without affecting filmproperties. For example, a 2% increase of TEOS flow in the inner regionof the substrate processing region 108 can result in a 2.6% increase indeposition rate on the inner region of the substrate. A 4% increase ofTEOS flow in the inner region of the substrate processing region 108 canresult in a 5.5% increase in deposition rate on the inner region of thesubstrate. In addition, a 2% decrease of TEOS flow in the inner regionof the substrate processing region 108 can result in a 2.0% decrease indeposition rate on the inner region of the substrate. A 4% decrease ofTEOS flow in the inner region of the substrate processing region 108 canresult in a 4.2% decrease in deposition rate on the inner region of thesubstrate.

Likewise, it has been observed that varying about 2-4% of TEOS flow(negligible amount of flow in the total process flow rate) in the outerregion of the substrate processing region 108 can result in about 1-2%change in deposition rates and film profile without affecting filmproperties. For example, a 2% increase of TEOS flow in the outer regionof the substrate processing region 108 can result in a 0.9% increase indeposition rate on the outer region of the substrate. A 4% increase ofTEOS flow in the outer region of the substrate processing region 108 canresult in a 1.5% increase in deposition rate on the outer region of thesubstrate. In addition, a 2% decrease of TEOS flow in the outer regionof the substrate processing region 108 can result in a 0.1% increase indeposition rate on the outer region of the substrate. A 4% decrease ofTEOS flow in the outer region of the substrate processing region 108 canresult in a 0.6% decrease in deposition rate on the inner region of thesubstrate.

In either case above, the total process flow of the gas mixtures in theinner gas zone 120/outer gas zone 142 may be about 10,500 sccm and thetotal TEOS flow in the inner gas zone 120/outer gas zone 142 may beabout 177 sccm to about 1650 mgm. Therefore, varying 2% of the TEOS flowis about 3.55 sccm to about 33 mgm (about 0.034% of total gas flow). Bychanging the flow rate of TEOS in the first and third gas mixtures(flowing to the inner region of the substrate processing region 108)and/or the flow rate of TEOS in the second gas mixture (flowing to theouter region of the substrate processing region 108), the depositionrates of the layer, e.g., oxides, can be adjusted to tune the edgeprofile of the deposited layer and/or the overall layer uniformity onthe substrate.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

The invention claimed is:
 1. A processing chamber for processing asubstrate, comprising: a first gas source comprising a first gas lineand a second gas line; a perforated lid; a gas blocker disposed on theperforated lid, the gas blocker comprising: a gas manifold; a centralgas channel formed in the gas manifold; a first gas distribution platedisposed below the gas manifold, the first gas distribution platecomprising an inner trench surrounding the central gas channel and anouter trench surrounding the inner trench, the central gas channelextending through the first gas distribution plate, bypassing the innertrench and outer trench; a first gas channel formed in the gas manifold,the first gas channel having a first end in fluid communication with thefirst gas line and a second end in fluid communication with the innertrench; a second gas channel formed in the gas manifold, the second gaschannel having a first end in fluid communication with the second gasline and a second end in fluid communication with the outer trench; asecond gas distribution plate disposed below the first gas distributionplate, the second gas distribution plate comprising a recess regioncomprising a ring shaped plenum in fluid communication with the outertrench, a central opening congruous with the central gas channel andbypassing the recess region, and a plurality of through holes formedthrough a bottom of the second gas distribution plate; and a third gasdistribution plate disposed below the second gas distribution plate, thethird gas distribution plate comprising a plurality of through holesformed through a bottom of the third gas distribution plate, and thethird gas distribution plate contacting a top surface of the perforatedlid; and a substrate support disposed below the perforated lid, thesubstrate support having a substrate supporting surface.
 2. Theprocessing chamber of claim 1, wherein the recess region is formed in atop surface of the second gas distribution plate, the recess regionsurrounding the central opening and extending radially between thecentral opening and an edge of the second gas distribution plate.
 3. Theprocessing chamber of claim 2, wherein the third gas distribution platecomprises: a recess region formed in a top surface of the third gasdistribution plate.
 4. The processing chamber of claim 3, wherein thethird gas distribution plate comprises: an inner ring defining an innergas zone of the third gas distribution plate, the inner gas zone beingin fluid communication with the inner trench; and an outer ringsurrounding the inner ring, wherein the inner ring and the outer ringare concentrically disposed between the second gas distribution plateand the third gas distribution plate, and wherein the inner ring and theouter ring defines an outer gas zone of the third gas distributionplate, and the outer gas zone is in fluid communication with the recessregion of the second distribution plate.
 5. The processing chamber ofclaim 1, wherein the through holes of the third gas distribution platehave a first density and the through holes of the second gasdistribution plate have a second density, and a ratio of the firstdensity to the second density is in a range of about 1.5:1 to about 5:1.6. The processing chamber of claim 1, wherein the inner trench has afirst depth and the outer trench has a second depth, and a ratio of thefirst depth to the second depth is about 1.1:1 to about 1.5:1.
 7. Theprocessing chamber of claim 1, wherein the first gas source comprises: asource of a first gas mixture comprising an oxygen-containing gas, asilicon-containing gas, and a carrier gas, wherein the source of thefirst gas mixture is in fluid communication with the first gas line; anda source of a second gas mixture comprising an oxygen-containing gas anda carrier gas, wherein the source of the second gas mixture is in fluidcommunication with the second gas line.
 8. The processing chamber ofclaim 7, further comprising: a second gas source comprising a third gasline in fluid communication with the central gas channel, and the secondgas source comprises a source of a third gas mixture comprising asilicon-containing gas and a carrier gas.
 9. The processing chamber ofclaim 8, wherein the oxygen-containing gas comprises (O₂), ozone (O₃),carbon dioxide (CO₂), carbon monoxide (CO), nitrous oxide (N₂O), nitrousoxide (N₂O), nitric oxide (NO), or any combination thereof, and thesilicon-containing gas comprises silane (SiH₄), tetraethoxysilane(TEOS), disilane (Si₂H₆), trisilane (Si₃H₈), tetrasilane (Si₄H₁₀), orany combination thereof.
 10. The processing chamber of claim 1, whereinthe central gas channel is formed through at least the gas manifold andthe first gas distribution plate, the first gas channel is disposedradially outward of the central gas channel, and the second gas channelis disposed radially outward of the first gas channel.
 11. A processingchamber for processing a substrate, comprising: a perforated lid; a gasblocker disposed on the perforated lid, the gas blocker comprising: agas manifold; a central gas channel formed in the gas manifold; a firstgas distribution plate disposed below the gas manifold, the first gasdistribution plate comprising an inner trench surrounding the centralgas channel and an outer trench surrounding the inner trench, thecentral gas channel extending through the first gas distribution plate,bypassing the inner trench and outer trench; a first gas channel formedin the gas manifold, the first gas channel having a first end configuredfor fluid communication with a first gas line of a gas source and asecond end in fluid communication with the inner trench; a second gaschannel formed in the gas manifold, the second gas channel having afirst end configured for fluid communication with a second gas line ofthe gas source and a second end in fluid communication with the outertrench; a second gas distribution plate disposed below the first gasdistribution plate, the second gas distribution plate comprising arecess region comprising a ring shaped plenum in fluid communicationwith the outer trench, a central opening congruous with the central gaschannel and bypassing the recess region, and a plurality of throughholes formed through a bottom of the second gas distribution plate; anda third gas distribution plate disposed below the second gasdistribution plate, the third gas distribution plate comprising aplurality of through holes formed through a bottom of the third gasdistribution plate, and the third gas distribution plate contacting atop surface of the perforated lid; and a substrate support disposedbelow the perforated lid, the substrate support having a substratesupporting surface.
 12. The processing chamber of claim 11, wherein therecess region is formed in a top surface of the second gas distributionplate, the recess region surrounding the central opening and extendingradially between the central opening and an edge of the second gasdistribution plate.
 13. The processing chamber of claim 12, wherein thethird gas distribution plate comprises: a recess region formed in a topsurface of the third gas distribution plate.
 14. The processing chamberof claim 13, wherein the third gas distribution plate comprises: aninner ring defining an inner gas zone of the third gas distributionplate, the inner gas zone being in fluid communication with the innertrench; and an outer ring surrounding the inner ring, wherein the innerring and the outer ring are concentrically disposed between the secondgas distribution plate and the third gas distribution plate, and whereinthe inner ring and the outer ring defines an outer gas zone of the thirdgas distribution plate, and the outer gas zone is in fluid communicationwith the recess region of the second distribution plate.
 15. Theprocessing chamber of claim 11, wherein the through holes of the thirdgas distribution plate have a first density and the through holes of thesecond gas distribution plate have a second density, and a ratio of thefirst density to the second density is in a range of about 1.5:1 toabout 5:1.
 16. The processing chamber of claim 11, wherein the innertrench has a first depth and the outer trench has a second depth, and aratio of the first depth to the second depth is about 1.1:1 to about1.5:1.
 17. The processing chamber of claim 11, wherein the central gaschannel is formed through at least the gas manifold and the first gasdistribution plate, the first gas channel is disposed radially outwardof the central gas channel, and the second gas channel is disposedradially outward of the first gas channel.